Device for supplying strip-like fabric by means of rollers

ABSTRACT

A device for guiding strip-like fabrics such as warp threads in looms provided with rigid rollers, at least one of which is driven, the rigid rollers being spaced around a flexible roller which presses against the rigid rollers, with the flexible roller, for example, being a fluid-filled tube.

United States Patent [1 1 Scheffel Au 14, 1973 DEVICE FOR SUPPLYING STRIP-LIKE FABRIC BY MEANS OF ROLLERS [56] References Cited [75] Inventor: Bemd Scheflel, Weissenburg/Bay, ITED S T S PATE TS Germany 3,050,972 8/1962 Noe 226/183 x 73 Assi nee: Walter Scheffel Weissenbur Ba l 1 g Germany g/ y Primary Examiner-Allen N. Knowles Assistant Examiner-Gene A. Church Flledl Dec. 21, Attorney Holman & Stem [21] Appl. No.: 210,362

[57] ABSTRACT A device for guiding strip-like fabrics such as warp 30 FiAlltiPrirltDta 1 D 3: 3: g ca on o y 20 62 859 5 threads in looms provided with rigid rollers, at least one "many of which is driven, the rigid rollers being spaced around a flexible roller which presses against the rigid rollers, [52] US. Cl. 226/183, 226/l9l with the flexible roller for exam ple, being a fluid-filled [51] Int. Cl B65h 17/22 tube. [58] Field of Search 226/183, 186, 191,

8 Claims, 4 Drawing Figures K Patented Aug. 14, 1973 3,752,378

2 Sheets-Sheet 1 Patnted Aug. 14, 1973 3,752,378

2 Sheets-Sheet 3 DEVICE FOR SUPPLYING STRIP-LIKE FABRIC BY MEANS OF ROLLERS BACKGROUND OF THE INVENTION This invention relates to a device for supplying striplike fabrics by means of rollers, in particular in looms, with one or more of the rollers being adapted to be driven.

By means of a loom, a strip-like fabric can be supplied which is formed on one side of the loom by warp threads and on the other side by tissue. In this case, the warp threads have previously been drawn off from a loom beam with .a brake, then subjected to a bend of approximately 90 and led to the loom. The tissue is drawn from out of the loom by means of a device which operates essentially on the principle of cable looping friction. In this case, two small rigid rollers are housed adjacent to a driven larger rigid roller and the tissue is wound around the rollers so that the result is as large as possible a looping angle on the driven roller. A looping warp stress K is exercised on the tissue. Transport of the strip-like fabric takes place as an initial stress force V is applied to the finished tissue before looping. This generally happens via a friction drive of a further roller which winds up the finished tissue.

The term K=V 'eha shows that a warp tension K can only arise when the initial stress V is applied by the tissue winding device. The friction coefficient [L is kept very large, with the driven looped roller being provided with a coarse covering such as, for example, corrugated sheet metal.

The principal disadvantages of such a device can be seen from the above formula. The object of the arrangement is transporting of the strip-like fabric at a speed corresponding to the speed of rotation of the driven looped roller accompanied by simultaneous production of as constant as possible a warp tension K behind the driven looped roller. However, according to the formula K is dependent on V and p Both are variables, so that K cannot be constant. In addition, variations of the braking force on the loom beam are transmitted directly into variations in the warp tension K. With such a device warp tension can only be controlled with very high tolerance.

A second disadvantage lies in the fact that a reversed supply direction of the strip-like fabric with winding of the warp threads on the loom beam leads to even greater variations in the warp tension K. Such a supply direction is, however, required whenever weft threads which have been incorporated by mistake are to be removed from the tissue.

OBJECTS AND SUMMARY OF THE INVENTION One object of the invention is to create a device which can provide accurate maintenance of the desired warp tension K during the supply procedure, in either direction, and in which the warp tension K is in no way dependent on the initial stress force V and the braking force on the loom beam.

To this end, the invention provides that at least three rigid rollers are housed around one flexible roller, with the flexible roller pressing against the rigid rollers. The strip-like fabric is led through the rollers so that it is pressed by the flexible roller against the three rigid rollers, preferably being looped around the flexible roller.

In a device according to the invention, no initial stress of the strip-like fabric is necessary and the surface of all rollers can be smooth as the strip-like fabric is always pressed by the flexible roller against the rigid rollers. It is also possible, by omitting an initial stress force, to supply the strip-like fabric in both directions with the device. The three rigid rollers support the flexible roller, whereby the flexible roller can be so deformed that it has a non-circular cross-section and has bulges which protrude between any two of the rigid rollers. l l

The flexible roller is, for example, a solid body made of rubber or foam. It is, however, expedient if the flexible roller is formed from a tube filled with fluid as the mounting of the flexible roller between the rigid rollers is then facilitated. A compressible gas can be used or a liquid when the tube comprises flexible material. This embodiment is particularly favorable as it is possible to adjust the normal force N direct via the filling pressure. The rigid rollers comprise, for example, steel and may have a plastic surface coating.

The invention further provides that a roller unit comprising the rigid rollers and the flexible roller is rotatably mounted around the axis of one of the rigid rollers which is adapted to be driven and co-operates with a speed adjustment drive. The speed adjustment drive facilitates driving of the rotatable roller unit with a directly adjustable supply speed.

If the supply-direction is provided on a loom, then a rotatable roller unit can supply the warp threads and a fixed roller unit, the tissue. In this case, it is preferable if none of the warp threads are accepted from a supply as the flexible roller presses every single warp thread against the rigid rollers. The strip-like fabric runs initially through the rotatably housed unit and then through the stationary-housed roller unit. If the stress of the strip-like fabric exceeds a predetermined value, then the pull of the strip-like fabric on the rotatable unit causes the unit to rotate slightly. By this means, the speed adjustment drive is actuated so that the supply speed of the rotatable unit rises and thus the stress in the strip-like fabric falls, and the rotatable unit reverts to its initial position.

In a device according to the invention, the strip-like fabric is conducted on its route from the loom beam to the tissue winding roller via two roller systems which succeed each other, are driven and work in a force locking manner. The warp tension K prevails between the two roller systems. Whereas the tissue-side roller system is driven at a constant speed corresponding to the desired tissue thickness, the speed of the warp-side roller can be controlled by a regulator which compares the actual warp tension with the adjusted theoretical value. If, for example, the warp tension is too high, then the regulator brings about an increased speed of the warp-side roller system with the result that the warp tension K is reduced.

Prerequisite to the working of such a device is a nonslip drive of the strip-like fabric in the roller systems. For this reason, the roller system associated with the device, according to the invention, transmits a drive force on to the strip-like fabric according to the following equation: K N t. In this case, the warp tension K is dependent only on a normal force N and the friction coefficient [1" For the case where N- t is greater than K, no slip can result. As N is a constant of the roller system and in addition y. is independent of the stresses prevailing in the strip-like fabric, both requirements of the invention are fulfilled: warp tension K independent of initial stress, braking force and supply direction.

In a device, according to the invention, with a fixed roller unit, and a rotatable roller unit the stress of the strip-like fabric between the fixed and rotatable roller units can be adjusted to a specific chosen value. In this case, the value can be established by a force, e.g., a spring or a weight, being fitted against which the rotatable roller unit must be rotated and which is intended to press the roller unit back into its initial position.

If the rollers are relatively long, then there is a risk that the rigid rollers will bend under the pressure of the flexible roller which would lead to a normal force N which would vary over the width of the strip-like fabric. In a critical case slip could then occur. For the case of a roller unit housed on a loom on the warp thread side, bending of the rigid rollers can be prevented when an endless taut strip is led on the outside around the rigid rollers. In this case, the endless strip lying on the surface of the rigid rollers runs in a reed mark formed by the warp threads. At the same time, this strip holds a supporting roller system in the gap between any two rigid rollers in such a way that their position is fixed geometrically in respect of each other and independent of the normal force or the warp tension. This type of support is well suited for the rotatable roller unit. Of course, bending of the rigid rollers can also be prevented by means of supporting rollers. This is advantageous in the case of the stationary-housed roller unit.

A device, according to the invention, can be used preferably for the supply of the warp tissue strip in looms. It can, however, be used for the supply of other strip-like fabrics which are similar to the strip-like fabrics used in looms. Thus, the device according to the invention can be used for supplying papers webs, plastic webs or thin sheets.

Preferred embodiments of the invention are described with reference to the attached drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a roller unit with three rigid rollers and one flexible roller;

FIG. 2 is a schematic and fragmentary perspective view of a loom in which roller units are housed on both the warp thread side and the tissue side;

FIG. 3 is a side view of a roller unit with supporting rollers; and

FIG. 4 is a side view ofa roller unit with strip and supporting rollers.

DETAILED DESCRIPTION OF THE INVENTION According to FIG. 1, three equal diameter rigid rollers l are so housed that their central axes lie at the corners of an equilateral triangle. A flexible roller 2, which presses radially outwardly and against the rigid rollers in the direction of arrows 3 is housed between the three rigid rollers l. The location of the rigid rollers need not always be as shown in FIG. 1; however, it must be such that the flexible roller always lies under pressure against the rigid rollers. A strip-like fabric 4 is so conducted around the flexible roller 2 that it is pressed by the latter against the rigid rollers l. Guiding of the strip-like fabric 4 can be seen in detail in FIG. 1.

According to FIG. 2, warp threads which form the strip-like fabric 4 are conducted in a loom, not shown in detail, in which they form a shed 5, behind which there results a tissue in the form of a strip-like fabric. The strip-like fabric 4 travels in the direction shown by an arrow 6 from right to left. A roller unit 7 is fitted in front of the loom and a further roller unit 8 behind the loom as a further transport device. Each of the roller units has rigid rollers l and a flexible roller 2 according to FIG. 1.

The roller unit 7 supplying the warp threads has an endless taut strip 9 which is conducted around the rigid rollers l on the outside and runs in a reed mark formed by the warp threads. It is also possible to arrange several endless strips at a distance from each other around the rigid rollers of a roller unit.

The rigid rollers l of both roller units 7, 8 are rotatably housed in two mountings 10, whereas the flexible roller 2 is housed freely between the rigid rollers. The roller unit 7 is rotatably housed at the height of the central axis of the upper rigid roller 1 in brackets 11. A support arm 12 is fitted to the rotatable mounting 10 and carries a weight 13. The strip-like fabric 4 supplied in the direction of the arrow 6 is intended, on the basis of the prevailing stress, to rotate the roller unit 7 against the force of the weight 13 around the central axis of the upper rigid roller.

A signal transmitter 14 in the form of an arm is connected to the rotatable mounting l0 and leads to a directly adjustable drive 15 and there supports a wheel 16. The wheel 16 drives via an endless chain 17 and wheel 18 the upper rigid roller of the rotatable roller unit 7. The drive 15 is a conventional V-belt drive whose transmission ratio changes when the arm 14 moves up or down. It is driven from a drive shaft 19 from which the second roller unit 8 is driven via a chain 20.

Support of the rigid rollers 1 of the rotatable roller unit 7 by means of supporting rollers can be seen from FIG. 4. All supporting rollers are attached to a frame 27 in rotatable manner but immovable in respect of each other. A supporting roller system 24 is enclosed in a suspended manner between any two of the rigid rollers l and the strip 9 so that the distance between the two rigid rollers 1 cannot change. To this end, a supporting roller system 24 has at least one roller 25 whose diameter corresponds roughly to the distance between the two rigid rollers 1. In addition, there are at least two rollers 26 present in the supporting roller system 24 whose task is to prevent the supporting roller system 24 being pressed so far inwards under the stress of the strip 9 that the roller 25 touches the flexible roller 2. A roller 28 is attached to the frame 27 in order to transmit the stress of the strip 9 on to the supporting roller system 24. More expediently with a total of three rigid rollers 1, two supporting roller systems 24 are enclosed by each strip 9.

As FIG. 3 shows in the fixed roller unit 8, the upper roller and the rear lower rigid roller 1 lie with that side, which faces the direction of the pull exercised on the roller by the strip-like fabric 4, against a supporting roller 22, 23. These two supporting rollers 22, 23 are housed in a stationary manner. Also housed in a stationary manner is a further supporting roller 23 which is so housed that the lower rigid roller 1 cannot avoid the pressure of the flexible roller 2.

In the illustrated embodiment, the strip-like fabric is laid in a looped manner around the flexible roller. It is also, however, conceivable to guide the strip-like fabric through the roller unit in such a way that it lies against only two rigid rollers. More than three rigid rollers can also be provided per roller unit. An electric-motor whose speed is controlled by means of a signal transmitter can also be provided as a drive with an adjustable drive speed. Control of the setting of the drive speed of the drive by means of the rotation of the rotatably housed roller unit can thus be realized with any known means in the prior art.

I claim:

1. A device for supplying strip-like fabric, including at least three rigid rollers, at least one of said rigid rollers being adapted to be driven, and an additional roller, characterized in that said rigid rollers are mounted about the additional roller, all said rigid rollers being rotatable in the same direction of rotation, and said additional roller being resiliently distortable, presses against the rigid rollers and is distorted thereby.

2. The device according to claim 1, characterized in that at least one endless taut strip is wound around the rigid rollers.

3. The device according to claim 1, characterized in that each of the rigid rollers adjoins locally fixed support rollers at that point which is facing in the direction of stress exerted by the strip-like fabric on said rigid roller.

4. A device for supplying strip-like fabric, including rigid rollers, at least one of said rigid rollers being adapted to be driven, and one flexible roller, characterized in that at least three rigid rollers are housed around said one flexible roller, said flexible roller pressformed from a tube filled with fluid.-

5. The device according to claim 4, characterized in that the fluid is compressed air.

6. The device according to claim 4 in which supporting rollers are provided against one of the rigid rollers on a side of said rigid roller which faces in the direction of pull exercised by the strip-like fabric on said rigid roller, at least one endles taut strip being wound around the rigid rollers, characterized in that a supporting roller system is enclosed between two of the rigid rollers and the endless strip.

7. A device for supplying strip-like fabric, including rigid rollers, at least one of said rigid rollers being adapted to be driven, and one flexible roller, at least three rigid rollers being housed around said one flexible roller, and said flexible roller pressing against the rigid roller, characterized in that a roller unit comprising said rigid rollers and said flexible roller is positioned in front of a drawing roller unit for the strip-like fabric and is rotatably housed around the axis of a rigid roller which is adapted to be driven, said unit cooperating with a signal transmitter linked with an adjustable drive.

8. A device for supplying strip-like fabric, including rigid rollers, at least one of said rigid rollers being adapted to be driven, and one flexible roller, at least three rigid rollers being housed around said one flexible roller, and said flexible roller pressing against the rigid rollers, characterized in that stationary supporting rollers are provided against the rigid rollers on the connecting line of the center points of the flexible roller and the rigid rollers.

* :r e a 

1. A device for supplying strip-like fabric, including at least three rigid rollers, at least one of said rigid rollers being adapted to be driven, and an additional roller, characterized in that said rigid rollers are mounted about the additional roller, all said rigid rollers being rotatable in the same direction of rotation, and said additional roller being resiliently distortable, presses against the rigid rollers and is distorted thereby.
 2. The device according to claim 1, characterized in that at least one endless taut strip is wound around the rigid rollers.
 3. The device according to claim 1, characterized in that each of the rigid rollers adjoins locally fixed support rollers at that point which is facing in the direction of stress exerted by the strip-like fabric on said rigid roller.
 4. A device for supplying strip-like fabric, including rigid rollers, at Least one of said rigid rollers being adapted to be driven, and one flexible roller, characterized in that at least three rigid rollers are housed around said one flexible roller, said flexible roller pressing against the rigid rollers, and the flexible roller being formed from a tube filled with fluid.
 5. The device according to claim 4, characterized in that the fluid is compressed air.
 6. The device according to claim 4 in which supporting rollers are provided against one of the rigid rollers on a side of said rigid roller which faces in the direction of pull exercised by the strip-like fabric on said rigid roller, at least one endles taut strip being wound around the rigid rollers, characterized in that a supporting roller system is enclosed between two of the rigid rollers and the endless strip.
 7. A device for supplying strip-like fabric, including rigid rollers, at least one of said rigid rollers being adapted to be driven, and one flexible roller, at least three rigid rollers being housed around said one flexible roller, and said flexible roller pressing against the rigid roller, characterized in that a roller unit comprising said rigid rollers and said flexible roller is positioned in front of a drawing roller unit for the strip-like fabric and is rotatably housed around the axis of a rigid roller which is adapted to be driven, said unit cooperating with a signal transmitter linked with an adjustable drive.
 8. A device for supplying strip-like fabric, including rigid rollers, at least one of said rigid rollers being adapted to be driven, and one flexible roller, at least three rigid rollers being housed around said one flexible roller, and said flexible roller pressing against the rigid rollers, characterized in that stationary supporting rollers are provided against the rigid rollers on the connecting line of the center points of the flexible roller and the rigid rollers. 